Dual wheel casters, because of their lower material cost due to their increased load carrying capability, and also because of their greater mobility characteristics than single wheel casters, have found considerable success in the support of data processing equipment.
When the equipment is not being moved from one position to another, it is desirable to immobilize the equipment and toward this end caster assemblies have been provided with various anti-swivelling and wheel braking devices that prevent movement of the caster or its wheel and hence immobilize the supported equipment. While such anti-swivelling and braking devices are adequate for most applications, there are instances where these anti-swivelling and braking devices are inadequate, such as when the equipment is supported on a hard non-shock absorbing floor surface that is subject to periodic vibration. In such cases, even with the most superior anti-swivelling and wheel-locking devices, the supported equipment will "walk" on these hard surfaces as the floors vibrate.
To alleviate this problem, it has been suggested that a conventional dual wheel caster be provided with a vertically adjustable foot that engages the floor to raise the caster wheels off the floor to reduce the possibility of article creepage. These caster feet, or "pads" as they are sometimes referred to, also have apertures to receive floor studs that permit the pads to positively lock to the floor, thus completely eliminating the possibility of article creepage. These permanent floor studs are arranged in parallel fashion in a room that may, for example, house a great number of data processing units in closely spaced side-by-side relation. This prior combination caster and support pad, however, does not adequately compensate for uneven floor surfaces, and sometimes presents an obstruction to the combination caster assembly when climbing a ramp.
It is a primary object of this invention to provide a combination caster and fixed support pad that ameliorates the problems noted above in both anti-swivelling and braking devices, as well as the problems in prior combination and caster and foot assemblies.